Electromagnetic characterization of Ni0.5Zn0.3Co0.2Fe2O4 bulk ceramics in the 1 MHz-12 GHz frequency range

In this paper, NiZnCo ferrite was produced by solid state synthesis, calcination at 1000 °C and sintering at 1250 °C in air atmosphere. The microstructure and phases of the sintered sample were analysed by scanning electron microscopy and X-ray diffraction, respectively. The magnetic properties of the ferrite were evaluated by magnetization and magnetostriction measurements. The complex magnetic permeability and complex permittivity were also measured between 1 MHz-12 GHz and the reflection loss (RL) was calculated in the 100 MHz-12 GHz frequency range. The results show that the ferrite sample presents magnetostrictive behaviour and a saturation magnetization of 71 Am2/kg. Complex permittivity measurements indicate that the material has dielectric behaviour in the whole frequency range studied, with ε′ varying between 7-40, and magnetic behaviour in frequencies between 1 MHz-5 GHz. The minimum RL was found at frequencies between 2.4-3.3 GHz and the calculated RL value for a thickness of 3 mm was lower than −10 dB in frequencies between 2.3-7.3 GHz. These results indicate potential application as microwave absorber in the S band